DURHAM, N.C., Feb. 28, 2014 (GLOBE NEWSWIRE) -- Chimerix, Inc. (Nasdaq:CMRX), a biopharmaceutical company developing novel, oral antivirals in areas of high unmet medical need, today released data from presentations at the 2014 BMT Tandem Meetings related to its investigational antiviral with broad-spectrum activity, brincidofovir (CMX001). Brincidofovir's antiviral activity against adenovirus (AdV) and its pediatric safety and tolerability data from a randomized, controlled clinical study and Chimerix's expanded access program were presented on Thursday, February 27, 2104 during the Supportive Care Oral Abstracts Session. Brincidofovir is an investigational oral nucleotide analog in Phase 3 development, currently enrolling adult hematopoietic cell transplant (HCT) recipients in the SUPPRESS trial for the prevention of cytomegalovirus infection, with secondary endpoints including clinical and virologic evidence of DNA viral infections, including AdV, BK virus and other herpes viruses such as HHV-6 and varicella zoster virus that contribute to morbidity and mortality in the first year following HCT.

Brincidofovir has been evaluated in the settings of preemption and treatment of adenovirus (AdV) infection, an often fatal viral infection with no approved therapy, in pediatric and adult immunocompromised transplant recipients. Study 202 was a randomized, placebo-controlled trial that evaluated early intervention with brincidofovir to prevent the development of AdV disease in HCT recipients. Study 350 was an open-label, expanded access trial of brincidofovir in immunocompromised patients with a life-threatening DNA viral infection, including AdV, and no alternative therapeutic intervention. This presentation analyzes clinical outcomes in a combined 21 subjects following initiation of brincidofovir at the time of asymptomatic AdV viremia. Subjects in the two studies received brincidofovir at a dose of 100 mg twice-weekly (adults) or 2 mg/kg twice-weekly (pediatrics). Baseline AdV viremia ranged from 100 copies/mL to 2.2 x 107 copies/mL (median 3,700 copies/mL), and became undetectable for 18 of 21 (86%) subjects at some time during treatment with brincidofovir, with a decline to undetectable in 14 of 21 (67%) subjects within the first week of dosing. The data from Study 202 and Study 350 support continued development of brincidofovir as a broad-spectrum antiviral.

Brincidofovir (CMX001) is Well Tolerated in Highly Immunocompromised Pediatric Patients

Brincidofovir's growing safety database of nearly 1,000 patients includes over 150 immunocompromised pediatric patients who have received brincidofovir through placebo-controlled studies or through Chimerix's expanded access program. This review of controlled and uncontrolled data in children as young as two months of age confirms a similar safety and tolerability profile as has been described in adult patients. In pediatric patients as in adults, there is no indication of hematologic or renal toxicity associated with brincidofovir therapy. Diarrhea was the most frequently reported side effect in both the pediatric and adult setting. In trials conducted following implementation of Chimerix's Safety Monitoring and Management Plan (SMMP) very few discontinuations of brincidofovir have been reported, allowing pediatric and adult subjects to complete the intended duration of dosing.

About Brincidofovir (CMX001)

Chimerix's lead product candidate, brincidofovir (CMX001), is an oral nucleotide analog that has shown broad-spectrum in vitro antiviral activity against all five families of DNA viruses that affect humans, including cytomegalovirus (CMV), adenovirus (AdV), BK virus (BKV) and herpes simplex viruses. Brincidofovir has a favorable safety and tolerability profile, with no evidence of kidney or bone marrow toxicity in nearly 900 patients dosed with brincidofovir to date. Chimerix believes that brincidofovir has the potential to be the first broad-spectrum antiviral for the prevention and treatment of clinically significant infections and diseases caused by DNA viruses.

Following positive Phase 2 results in CMV, in the third quarter of 2013 Chimerix initiated the Phase 3 SUPPRESS trial which will support Chimerix's initial regulatory submission for prevention of CMV infection in adult hematopoietic cell transplant (HCT) recipients. In September 2013, data from this Phase 2 trial were published in the New England Journal of Medicine (N Engl J Med 369:1227-36). Chimerix recently presented results from its Phase 2 trial in AdV, an often-fatal infection with no approved treatment. In this study, a brincidofovir dose of 100 mg twice weekly demonstrated an antiviral effect on levels of AdV in the blood, and a numeric decrease in overall mortality. Chimerix continues to work with the Biomedical Advanced Research and Development Authority (BARDA) to develop brincidofovir as a medical countermeasure against smallpox.

About the Phase 3 SUPPRESS Trial

SUPPRESS is designed to demonstrate the efficacy and safety of brincidofovir for the prevention of CMV infection versus a placebo control, as no therapy is currently approved for the prevention of CMV in HCT recipients. The primary endpoint for SUPPRESS is the rate of clinically significant CMV infection through the first 24 weeks post-transplant. The trial is powered to detect a relative 50% decrease in clinically significant CMV infection in subjects receiving brincidofovir versus those receiving placebo. Secondary endpoints in the SUPPRESS trial include clinical and virologic evidence of DNA viral infections, including AdV, BKV and other herpes viruses such as HHV-6 and varicella zoster virus that contribute to morbidity and mortality in the first year following HCT.

SUPPRESS is anticipated to enroll approximately 450 HCT recipients who are at increased risk of CMV infection, with approximately 300 subjects receiving 100 mg twice weekly brincidofovir and 150 receiving placebo (2-to-1 ratio). Approximately 40 transplant centers will participate in SUPPRESS. Dosing of study drug will begin shortly after subjects receive their transplant, and will not require evidence of stem cell "engraftment" (evidence of production of blood cells by the new transplant), a safety precaution incorporated in the Phase 2 trial of brincidofovir and other recent trials of investigational antivirals for CMV prevention. Enrolled subjects will continue on brincidofovir or placebo through Week 14 post-transplant, the period of highest risk for viral reactivation. Subjects will continue to be monitored for evidence of CMV and other DNA viral infections through Week 24 post-transplant.

Data from SUPPRESS are anticipated in mid-2015 and, if positive, may support Accelerated Approval of brincidofovir for the prevention of CMV infection.

About Cytomegalovirus (CMV)

CMV is a member of the herpes virus family and is the most common infectious pathogen in transplant recipients. A majority of adults in the US have been exposed to CMV, generally in childhood, with lifelong viral latency established following resolution. In healthy individuals with a functioning immune system, CMV remains dormant throughout life. A functioning immune system protects an infected individual against future exposure to CMV but does not clear the virus from their body. In immunocompromised individuals with weakened immune systems, such as transplant recipients, CMV often reactivates during the post-transplant period when the immune system is rebuilding itself. No therapies are approved for the prevention of CMV in HCT recipients. Currently available systemic anti-CMV agents can be effective against CMV; however, their use is limited by significant toxicities, including bone marrow suppression and renal impairment, and these therapies are only approved for certain solid organ transplant patient populations. CMV infection is known to correlate with progression to CMV disease and death. CMV itself is immunosuppressive and reactivation of the virus can predispose a patient to other opportunistic viral infections in addition to fungal and bacterial infections.

About Chimerix

Chimerix is a biopharmaceutical company dedicated to developing and commercializing novel, oral antivirals in areas of high unmet medical need. Chimerix's proprietary technology has given rise to two clinical-stage nucleotide analog lipid-conjugates, brincidofovir (CMX001) and CMX157, which have potential for enhanced activity and safety in convenient, orally administered dosing regimens. Chimerix's lead product candidate, brincidofovir, is an oral nucleotide analog that has shown broad-spectrum in vitro activity against all five families of DNA viruses that affect humans, including CMV, AdV, BKV and herpes simplex viruses. In the third quarter of 2013, Chimerix initiated the Phase 3 SUPPRESS trial of brincidofovir for the prevention of CMV infection in adult HCT recipients, also known as bone marrow transplants. Brincidofovir has received Fast Track designation by the FDA, and the Phase 3 data, if positive, may support Accelerated Approval of brincidofovir for the prevention of CMV infection in adult HCT recipients. Chimerix continues to work with the Biomedical Advanced Research and Development Authority (BARDA) to develop brincidofovir as a medical countermeasure against smallpox. Chimerix's second product candidate, CMX157, an oral nucleotide analog for treatment of HIV infection, was licensed to Merck in July 2012. For further information, please visit Chimerix's website, www.chimerix.com.

Forward-Looking Statements

Statements contained in this press release regarding matters that are not historical facts are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Risks are described more fully in Chimerix's filings with the Securities and Exchange Commission, including without limitation its most recent Quarterly Report on Form 10-Q, its most recently filed reports on Form 8-K and other documents subsequently filed with or furnished to the Securities and Exchange Commission. All forward-looking statements contained in this press release speak only as of the date on which they were made. Chimerix undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.

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